The sixth season of British science fiction television series Doctor Who began on 10 August 1968 with the first story of season 6 The Dominators and ended Patrick Troughton's reign as the Doctor with its final story The War Games. Only 37 out of 44 episodes are held in the BBC archives; 7 remain missing. As a result, 2 serials are incomplete: only episode 2 of the 6-part story The Space Pirates still exists, while The Invasion has had its two missing episodes reconstructed using animation.

The Dominators is the first serial of the sixth season of the British science fiction television series Doctor Who, which originally aired in five weekly parts from 10 August to 7 September 1968. The Second Doctor and his travelling companions Jamie McCrimmon and Zoe Heriot work with the Dulcians of the planet Dulkis to prevent the alien Dominators from blowing up Dulkis and using its irradiated remains as spaceship fuel.